Regional Extent of Steppe Tundra

Steppe-tundra environments were not restricted to Beringia during the Pleistocene glaciations. They spread to the southwest in Eurasia, forming a band south of the ice sheets that reached the middle of Europe and southern Britain and Ireland. Thus, the Pleistocene steppe-tundra was one of the largest ecosystems (in terms of geographic area) of the last few million years. There are indications that the Bering Strait region formed an ecological barrier between eastern and western steppe-tundra regions. The mesic (medium moisture) shrub tundra that dominated parts of the land bridge may have formed a barrier to steppe-tundra species. For instance, the woolly rhinoceros lived throughout the steppe-tundra regions of Eurasia, but never became established east of the Bering Land Bridge (that is, in Alaska and the Yukon Territory). This species lived in dry steppe-tundra habitats, dominated by grasses and other herbs. The dwarf shrubs and mosses that flourished on the Bering Land Bridge may have blocked its entry into the New World.

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